JP2000-291499A, published by the Japan Patent Office in 2000 proposes a fuel supply device which reforms a gasoline fuel before supplying it to an internal combustion engine. The device extracts a reformate gas containing hydrogen and carbon monoxide by causing a partial oxidation reforming reaction and a steam reforming reaction in the gasoline fuel. The residual fuel which has not undergone the reforming reaction is a high-octane-number fuel which has a relatively small molecular mass.
The reformate gas has a high combustion speed and brings about an effect of ensuring that the ignition of a fuel-air mixture, and hence the stability of combustion, is enhanced in a state where the internal combustion engine performs a lean burn operation.
In contrast, the high-octane-number fuel prevents knocking from occurring in the internal combustion engine, which results in an increase in the output torque and the heat efficiency of the internal combustion engine.